Synergistic fungicidal composition for the control of diseases of rice plants

ABSTRACT

Fungicidal compositions in the form of synergistic combinations of 4,5,6,7-tetrachlorophthalide and O-(ethyl, n-propyl or isopropyl)-S,S-diphenylphosphorodithiolate which are individually known compounds, which combinations possess synergistic fungicidal properties especially for the control of diseases of rice plants.

United States Patent 1191 ,Ysmada.

[54] SYNERGISTIC FUNGICIDAL Y COMPOSITION FOR THE CONTROL .OF DISEASES OF RICE PLANTS [75] Inventor: Yasuo Yamada, Tokyo, Japan [73] Assignee: Bayer Aktiengesells'chaft, Leverkusen, Germany [22] Filed; Nov. 17, 1970 [21] Appl. No.: 90,466

[30] Foreign Application Priority Data I Nov. 24, 1969 Japan ..44/93773 [52 us. c1 ..424/22s, '424/279 51 Im. c1. ..A0ln 9/02, AOln 9/28, AOln 9/36 [58] Field of Search ..424/225, 279; 260/2433 [56] References Cited UNITED STATES PATENTS 3,499,951 3/1970 Schrader a a1.' .424/22s [451 Mar; 27, 1973 FOREIGN PATENTS OR APPLICATIONS 6,8 1 1,990 2/1969 Netherlands 6,61 1,810 2/1967 Netherlands 6,61 1,860 2/ 1967 Netherlands om PUBLICATIONS Chem. Aim. v01. 52, 10,001 1953 Primary Examiner-Jerome D. Goldberg Assistant Examiner-Allen J. Robinson 7 Attomey-Burgess, Dinklage & Sprung ylpho'sphorodithiolate which are individually known compounds, which combinations possess synergistic fungicidal properties especially for the control of diseases of rice plants.

10 Claims, No

' 14.9944/63). It has been furthermore found that when SYNERGISTIC FUNGICIDAL COMPOSITION FOR THE CONTROL OF DISEASES OF RICE PLANTS The present invention relates to and has for its objects the provision of particular new fungicidal compositions in the form of synergistic combinations of 4,5,6,7-tetrachlorophthalide and O-(ethyl, n-propyl or isopropyl)-S,S-diphenylphosphorodithiolate which are individually known compounds, which combinations possess outstanding synergistic fungicidal properties especially for the control of diseases of rice plants, optionally in the form of carrier composition mixtures of such synergistic combinations with solid and/or liquid dispersible carrier vehicles, and methods for using'such synergistic combinations in a new-way especially for combating diseases of rice plants, with other and further objects becoming apparent from a study of the within specification and accompanying examples.

The aforementioned combination has excellent synergistic preventive and curing effects with a prolonged duration of action in controlling diseases of rice plants, particularly blast (caused by Piriculariq oryzae) and sheath blight (caused by Pellicula'ria s'asakii). The combination is also characterized by excellent adaptability in application andlow toxicity to men and domestic animals. I

It has been found that when two known insecticides are mixed together,- the insecticidal activity can be doubled (Japanese Patent No. 438,268; Patent Publication No. 2079,2/64) and the immediate effect and duration of insecticidal activity are increased (Japanese Patent No. 490,900; Patent Publication No. 10038/66). It has also been found that when known fungicides andinsecticides are mixed together, fungicidal and insecticidal effects can be obtained simultaneously (Japanese Patent No. 414130; Patent Publication No.

two known insecticides applicable to different ranges of pests are mixed, the range of application of the mixed insecticide is broadened, (Japanese Patent No. 469,435; Patent Publication No. 2 2399/65). These proposals have been made with aview to increasing or doubling synergistically the known activities of the chemicals to be used.

- has now surprisingly been found that when two particular compounds of different types, namely a particular substituted phthalide and an organic phosphoric acid ester of a certain group, which possess different properties as fungicides, are mixed together, the preventive and curative effects of each component for controlling rice blast can be increased by the synergistic action of both components. The mixed fungicide of this invention has the valuable characteristic that and 2. an O-alkyl-S,S-diphenylphosphorodithiolate of the generalformula wherein I R is alkyl of two or three carbon atoms, alone or in admixture with a diluent or carrier.

The composition preferably contains ingredients (I and (II) in a weight ratio of from 4 to 1:1.

The invention also provides a method of combating fungus pests (especially in rice cultivation) which comprises applying to the pests or a habitat thereof a cqm position according to the invention.

The invention also provides protection to crops (especially rice crops) from damage by fungus pests by being grown in areas to which, immediately before or during the time of the growing, a composition according to the invention was applied.

It has previously been suggested that compounds of a broad range including compounds of the above formula '(II) can be used as fungicides (Dutch SpecificationNo; 66-11860). As a result of research carried out in connection with the present invention it has. been found that the compounds of the formula (II) are effective against blast.

It has now verysurprisingly. been found thatwhen amixture of the compound of formula (I) and, a com pound of formula (II) is used as a fungicide in the cultivation of rice plants, greatly improved results can, be obtained.

Rice plants are susceptible to various types of damage caused not only by harmful insectsbut also bythe damage caused by blast is greatest.

limitation of the application period imposed on each or /C 2 Cl I c0 c! (I) According to the research carried out in connection with the present invention, fungicides of above formulas (I) and (II), like all the organic synthetic compounds developed up to now, lack one or two of three factors required in controlling diseases of {rice plants, namely a preventive effect, acurative effect and-prolonged duration of the effect, and they are insufficiently effective when used inpractice, particularly-for controlling blast which is a very serious disease. of rice plants, and these compounds are less effectivethan the. conventional strong fungicides containing. dangerous heavy metals.

It is quite unexpected that the above problem is solved by combining'the fungicides of formulas (I) and. (II). This combination can. overcome common defects of organic synthetic compounds developed up to the present, and the mixed fungicides of this invention can be said to be a newly developed fungicide beingfree of any heavy metal in use for cultivation of'rice plants. Such combination will replace organic mercury com: pounds containing a heavy metal harmful to men and domestic animals which have been hitherto used in this field.

Organic phosphoric acid esters of formula (II) to be used in this. invention, namely O-alkyl-,S,-diphen ylphosphorodithiolates, can be prepared by the method licularia, sasakii), brown spot (disease caused by Cochliobolus' miyabeanus), stem+rot (disease caused by Helminthosporium sigmoideum) and bacteria leaf blight (disease caused by Xanthomonas oryzae).

The mixed fungicides of this invention may be prepared by mixing the specific compound of formula (1) and at least one specific compound of formula (11), and may contain an inert gaseous, liquid or solid diluent or carrier, optionally with additional compounds such as surfactants, emulsifiers, dispersing agents, spreaders, wetting agents and stickers, as are used in agriculture, and they may be used in various forms.

As a gaseous diluent or carrier there may be cited Freon and other-aerosol propellents which are gaseous under normalconditions.

The particular synergistic combinations of active compounds according ,to the instant invention can be utilized, if desired, in theforrn :of the usual formulations orcompositions 'withconventional inert, (i.e., plant compatible or herbicidally inert) pesticide diluents or extenders, i.e. diluents or extenders of the type usable inconventional pesticide formulations or compositions, e.g. conventional pesticide dispersible carrier vehicles, such as solutions, emulsions, suspensions, emulsifiable concentrates, spray powders, pastes, soluble powders, dusting agents, granules, etc. These-are prepared in known manner, for instance by extending the synergistic combination of active compounds with conventional pesticide dispersible liquiddiluent carriers and/or dispersible solid carriers optionally with the use of carrier vehicle-assistants, e.g. conventional pesticide surface-active agents, including emulsifying agents and/or dispersing agents, whereby, for example, in the case where water is used as diluent, organic solvents may be added as auxiliary solvents. The following may be chiefly considered for use as conventional carriervehicles for this purpose: inert dispersible liquid diluent carriers including inert organic solvents, such as aromatic hydrocarbons (e.g. benzene, toluene, xylene,

etc.), halogenated, especially chlorinated, aromatic hydrocarbons (e.g. chlorobenzenes), paraffins (e.g. petroleum fractions), chlorinatedaliphatic hydrocarbons (e.g. methylene chloride, etc.), alcohols (e.g. methanol, ethanol, propanol, butanol, etc.), ethers, ether-alcohols (e.g. glycol monomethyl ether, etc.), amines (e.g. ethanolamine, etc.), amides (e.g.,dimethyl formamide, etc.), sulfoxides (e.g. dimethyl sulfoxide, etc.), ketones (e.g. acetone, etc.-), and/or water; as well as inert dispersible finely divided solid carriers, such as ground natural minerals (e.g. kaolins, alumina, silica or quartz, chalk, i.e. calcium carbonate, talc, kieselguhr, etc.), and ground synthetic minerals (e.g. highly dispersed silic'ic acid, silicates, e.g. alkali silicates, etc.),

whereas the following may be chiefly considered for use as'conventional carrier vehicle assistants, e. g. surface-active agents, for this purpose: emulsifying agents, such as nonionic and/or anionic emulsifyingagents(e.g. polyethylene oxide esters of fatty acids, polyethylene oxide ethers of fatty alcohols, alkyl sulfonates, aryl sulfonates, etc., and especially 'alkyl aryl-polyglycol ethers, magnesium stearate, sodium oleate, etc.); and/or dispersing agents, such as lignin, sulfite waste liquors, methyl cellulose, etc.

As will be appreciated by the artisan, the synergistic combination of active compounds according tothe instant invention may be employed alone or in the form of carrier composition extended mixtures with such solid and/or liquid dispersible carrier vehicles and/or with other known compatible active agents, especially agricultural chemicals such as insecticides, nematocides, fungicides (inclusive of antibiotic substances) herbicides, growth-adjusting agents, fertilize'rs and fer tilizing substances, if desired, or in the form of particluar dosage preparations for specific application made therefrom, such as solutions, emulsifiable liquids, concentrated emulsions, wettable powders, soluble powders, pastes, oils, aerosol preparation, furnigating agents, dusts, particles, coated particles, tablets, granules and pellets.

The mixed fungicide of thisinvention may be applied to pathogenic fungi or places where pathogenic fungi live directly or by means of a tool in accordance with a spraying, scattering, atomizing, misting, dusting, particle-scattering', mixing, fumigating, injecting or powdercoating method. It is alsopossible to apply the mixed fungicideof this invention inaccordance with the so-' called ultra low-volume? spraying method. In this method it is possible to increase the concentration of the active mixing components to 95 percent, and even up to 100 percent. 1n actual application, the concentration of the, active components in the ready-to-use preparation may be varied within a broad range for the same reasons described in respect to the preparation form. It is generally preferred that the concentration of the total of the two active components is 0.005-10 percent by weight, especially 0.0l-5.0 percent by. weight. The amount applied of the fungicide of'this invention is about 15-1 ,000 g per 10 ares, preferably 40 -600 g per 10 ares, reckoned as the total of the'two activecomponents. It is possible or sometimes necessary to apply the fungicide in an amount exceeding or belowthe above ranges. I l I According to this invention there are provided the following methods of controlling and preventing diseases of rice plants with the use of the above-mentioned fungicidal composition of this invention:

l. A method of controlling and preventing diseases of rice plants characterized by applying a mixture of the active compounds of this invention and/or a mixed fungicide'containing them to places where rice plants grow (inclusive of water surfaces and soils of paddy fields) and/or rice plants, and

2. Amethod of cont rollingand preventing blast of rice plants characterized by applying a mixture of ac- 65 tive compounds of this invention and/or a mixed fungicide containing them to places where rice plants grow (inclusive of water surfaces and soils of paddy fields) and/or rice plants before, during or after occurrence of blast in rice plants.

This invention is illustrated, without'limitation, by

the following examples:

EXAMPLE 1 about 1,000 2,000 times by volume) to obtain-the desired concentration of the active compounds. The ready-to-use preparation thus produced was sprayed on pathogenic fungi or places where they grow by means of a sprayer.

EXAMPLE 2 In the same manner as in Example 1, emulsifiable concentrates (emulsion preparations) of the active compounds of formulas (I) and (II) were prepared separately. Each liquor was diluted with water (about 500 1,000 times by volume) until the concentration of the active compound reached the desired value. The

suspensions thus produced were mixed together before spraying (mixing ratio 1:1) (by a tank mixing method) to form a ready-to-use preparation, which was sprayed in the same manner as in Example 1.

EXAMPLE 3 EXAMPLE 4 A mixture (2 percent) by weight of active compounds of formulas (I) and (II) in a mixing ratio of 1:1 and a'mixture (98 percent) by weight of talc and clay in a mixing ratio of EM were mixed together by means of a mixing apparatus (such as a Lodecke mixer) and made homogeneous by a grinding mill to form a dust formulation. This formulation thus produced was directly applied to stems and leaves of rice plants at a rate of 3 4 Kgper l ares by means of a dusting machine.

EXAMPLE 5 A 3:1 mixture of active compounds of formulas (I) and (II) was dissolved in a solvent (for instance, acetone) and the solution was sprayed on clay particles of a diameter of 0.2 1 mm while mixing the clayparticles'by means of a mixing apparatus (for instance, V- t'ype mixer) until the concentration of the active compounds was 5 percent by weight in the particles. Thereafter, the solvent was evaporated and the particles were dried to form ready-touse particles. They were directly applied to thewater surface or soil-of th paddy field at a rate'of 4 6 Kg per 10 ares.

Test results showing heretofore unknown, excellent synergistic effects attained by the fungicides of this in: vention and mixtures thereof will now be given.

EXAMPLE 6 Test against blast Piricularia oryzae) of rice plants (pot test) The effects of theactive component of formula (I), 4,5,6,7-tetrachlorophthalide, the active component of formula (II), O-alkyl-S,S-diphenylphosphorodithiolate and mixtures of these two components against blast'of rice plants were examined .by the following test procedures. The results are shown in Table 1 and 2. Test procedures:

Carrier 5 parts by weight of clay Emulsifier l part by weight of polyoxyet'hylene alkylarylether To prepare a suitable preparation of the active compound, 1 part by weight of the mixed fungicide of this invention or each of the active compound was thoroughly mixed with the stated amount of carrier and the stated amount of emulsifier. The obtained wettable powder was then diluted with water to the desiredconcentration. I

a. Test of protective effects against rice blast and residual thereof:

Rice plants (jukkoku variety) were cultivated in a pot of 12 cm diameter. The preparation of this inven- @tion and'each of the active compounds were sprayed separately atthe tillering stage until dripping wet.

A half of the treated pots was kept in a chamber maintained at 25 C and a relatively humidity of 100, percent for 2 days from the next day. after the chemical spraying, and the remaining half was kept in the same chamber for 2 days from the fifth day after the chemical spraying. While kept in the chamber, thericeplants were inoculated twice with a suspension of spores of artificially cultured pathogenic fungi of blast (50,000 100,000 spores/ml) by spraying. From the resultsofthe inoculation made the next day after the chemicalspraying, the protective effect can be evaluated, and from.

the results of-the inoculation made the fifth day after the chemical spraying, the residual-effect (the durabili:

ty of the effect of chemicals)can be ascertained.- Seven days after the inoculation, l0 stems were selected from each pot and the damage degree of the uppermost 2 developed leaves were measured. The phytotoxicity of This test was conducted to evaluate: the curative ef fect of the test chemicals against the pathogenic-fungi which had infected rice plants and caused the disease.

Rice plants of the same variety. as used intest (a), ofthe protective effect were kept in achamber-maintained at 25 C and a relative humidityof percent for2 days,

same manner as in the test of the protective effect and the damage degree was calculated.

Disease attack degree Ratio of areas on which disease spots appear 0 0.5 less than 2% l 2 6 10% 3 l1 20% 4 21 40% 5 more than 40% Damage degree rn n, 2n 4n 8n, l0n )/l0 N X 100 attack attack attack attack attack attack leaves of a disease TABLE 1 Test results of effects against blast of rice plants (pot test) Wettable Preparation (Wettable powder) Active Phytocomponent Damage degree toxicity Sample concen-' 'protectresicurative ive dual compound tration effect effect effect (1) 0 0.25 6.4 13.7 66.7 0.05 O 1.2 69.2 (11) 0.025 5.1 33.4 8.0 .05 1.0 20.6 0.3 (l)+(ll)(1:1) mixed fungicide 0.025 4.3 16.7 9.3 of this 0.5 O 2.2 0.3 invention (l)+ (ll )(2:l) mixed fungicide 0.025 5.0 14.3 14.5 of this 0.5 0 1.0 1.7 invention Untreated 40.6 56.7 59.0 control Notes: l)(l) 4,5,6,7-tetrachlorophthalide (l1) 0-ethyl-S,S-diphen-. ylphosphorodithiolate 2) The symbol in the "Phytotoxicity" means that the chemical did not give any adverse effect on the growth of rice.

0. Test on effects against Leaf Blast of rice plant (Field-test) k Diluent 97 parts by weight of talc To prepare a suitable preparation of the mixed fungicide of this invention or each of the active compound, 3 parts by weight of active compound were thoroughly mixed with the stated amount of diluent by crushing and mixing. The obtained dust was directly applied.

Rice plants were cultivated on a rectangular field (1m X 2m)in a customary manner and the preparation of the test chemicals (dust formulation) were applied at the time when naturally infected'blast came to appearv on leaves of rice plants. The influences of the relation.

between the time of appearance of the disease and the. time of application of the said preparation of test chemicals on the blast-controlling effects were examined.

a. Variety of rice plant: Asahi (susceptible to blast) b. Sowing date and amount of seeds: July 17 and g/lm I c. Testing areas: Each area was-l m? and total was 3 m to each test chemicals.

d. Chemical-applying time and amount applied of chemical:

Protective effect-test areas;

First time August 4 (before appearance of the dis ease) 7 Second time August 10 (initial stage of the disease) i Curative effect-testing areas; I First time August 10 (initial stage of the disease) Second time August 16 (advanced stage of the disease) I The preparation of test chemical (dust formulation) was applied homogeneously by means of a small hand duster in an amount of 4 Kg '(120 g of activein-f g'redient)/ 10 ares.

e. Examination date and examination procedures;

Examination date August30 v j H With respect to optionally selected 50 stems per one area, the ratio of the area on which disease spots appeared was examined according to the following Stan dard of Examination of Disease Degree of Leaf Blast (Principle of Examination of Control and Prevention of Diseases of Ordinary Plants by Fungi and insects compiled by Ministry of Agriculture and Forestry, Agricultural Administration Bureau, in September, 1965).

Standard of the disease degree of Leaf Blast;

The degree of the disease appearance of Leaf Blast was classified into grades shown in the following table according to the standard chart for examination of the disease degree of Leaf Blast.

KR; Orai'ssst sstsgga;ag

leaves Area of whole leaves natiadrares or? which spots appeared X (The area of whole leavesdid notcontain the area of leaf sheath or naturally withered leaf.)

' (ratio of area on (ratio of area on which disease which disease spots appeared spots appeared in the untreated in the treated area) area) (ratio of area on which disease spots appeared in the untreated area) Controlling: value area 7 TABLE2 Test results of effects against Leaf Blast of rice plants Protective effect Curative effect Test chemicals ratio of Control Ratio of area Controlling area ling (active on which value on which value ingredient disease disease spots spots g l appeared appeared ares I I20 5.0 94 68.6 ll I 20 21.5 74 6.7 91 l+ ll 80+40 3.7 96 7.2 90 Untreated 82.6 0 72.4 0

control Note: In Table 2, the chemicals (l) and (ll) are the same as in Table 1.

' synergistic combinations of active compounds to such plants and/or their habitat.

It will be appreciated that the instantspecification and examples are set forth by way of illustration and not. limitation, and that various modifications and changes may be made without departing from the spirit and scope of the present invention.

Whatis claimed is: v

l. A synergistic fungicidal compositioncontaining as active ingredients (1) 4,5,6,T-tetrachlorophthalide of the formula wot]. d av I /C z C1- 1 CO C] (I) and (2) an O-alkyl-S,S-diphenylphosphorodithiolate of the formula wherein R IS alkyl of two or three carbon atoms, compounds (I) and (II) being present in a weight ratio of about 4 to 1:1.

2. The synergistic fungicidal composition according to claim 1 containing as active ingredients(l) 4,5,6,7- tetrachlorophthalide and 2) O-ethyl-S,S-diphenylphosphorodithiolate.

3. The synergistic fungicidal composition according to claim 1 containing as active ingredients (1) 4,5,6,7 tetrachlorophthalide and 2) O-n-propyl-S,S-diphenylphosphorodithiolate.

4. The synergistic fungicidal composition according to claim -1 containing as active ingredients (1) 4,5,6,7- tetrachlorophthalide and (2) O-iso-propyl-S,S-diphenylphosphorodithiolate.

5. The synergistic composition according to claim 2 which contains from 0.1 to 95 percent by weight of the total of ingredients (l) and (ll), and a pesticide carrier.

6. A method of combating fungus pests which comprises applying to the pests or a habitat thereof a fungicidally effective composition according to claim I.

7. The method according to claim 6 in which a composition is used containing from 0.005 to 10 percent by weight of the total of ingredients (I) and (II), and a pesticide carrier.

8. The method according to claim 6 in which the composition is applied to an area of rice cultivation.

9. The method according to claim 6 in which the pests are rice blast or sheath blight causative organ- 181118.

10. The method according to claim 6, in which "the composition is applied in an amount of 15 to 1,000'g of the total of ingredients (l) and (ll) per 10 ares. 

2. The synergistic fungicidal composition according to claim 1 containing as active ingredients(1) 4,5,6,7-tetrachlorophthalide and (2) O-ethyl-S,S-diphenylphosphorodithiolate.
 3. The synergistic fungicidal composition according to claim 1 containing as active ingredients (1) 4,5,6,7-tetrachlorophthalide and (2) O-n-propyl-S,S-diphenylphosphorodithiolate.
 4. The synergistic fungicidal composition according to claim 1 containing as active ingredients (1) 4,5,6,7-tetrachlorophthalide and (2) O-iso-propyl-S,S-diphenylphosphorodithiolate.
 5. The synergistic composition according to claim 2 which contains from 0.1 to 95 percent by weight of the total of ingredients (I) and (II), and a pesticide carrier.
 6. A method of combating fungus pests which comprises applying to the pests or a habitat thereof a fungicidally effective composition according to claim
 1. 7. The method according to claim 6 in which a composition is used containing from 0.005 to 10 percent by weight of the total of ingredients (I) and (II), and a pesticide carrier.
 8. The method according to claim 6 in which the composition is applied to an area of rice cultivation.
 9. The method according to claim 6 in which the pests are rice blast or sheath blight causative organisms.
 10. The method according to claim 6, in which the composition is applied in an amount of 15 to 1,000 g of the total of ingredients (I) and (II) per 10 ares. 